Reflexes, or reflex actions, are involuntary, almost instantaneous movements in response to a specific stimulus. Reflex arcs that contain only two neurons, a sensory and a motor neuron, are considered monosynaptic. Examples of monosynaptic reflex arcs in humans include the patellar reflex and the Achilles reflex.
A microwave oven uses microwaves. This is a kind of electromagnetic wave. The energy source for the microwave oven is AC (alternating current, electricity), available in many houses.
Microwaves, which we use for cooking and for communication, are short wavelength radio waves with wavelengths between a few and a few hundred millimeters (tenths of inches to tens of inches).